Resolution of thoracic limb lameness associated with traumatic suprascapular neuropathy in a dog: case report

Background: Traumatic suprascapular nerve injury is well recognized in both horses and humans, however, the condition has not been reported in dogs. The suprascapular nerve innervates the infraspinatus and supraspinatus muscles, and trauma of the nerve can result in profound atrophy of these muscles and mechanical lameness. Case presentation: A 4-year-old male neutered Cocker Spaniel was presented with moderate lameness of the left thoracic limb and severe muscle atrophy of the supraspinatus/infraspinatus muscles. Gait alterations included abduction of the elbow joint during the weight bearing phase, resembling those observed in dogs with infraspinatus contracture. Magnetic resonance imaging of the caudal cervical spine and left thoracic limb revealed segmental enlargement of the left suprascapular nerve at the level of the cranial endplate of C7 and marked diffuse homogenous signal changes and atrophy of the left supraspinatus and infraspinatus muscles. Electromyography revealed moderate to severe spontaneous activity isolated to the supraspinatus and infraspinatus muscles consistent with denervation. The patient was presumptively diagnosed with traumatic suprascapular nerve injury and, following a period of exercise restriction, exhibited a marked improvement in clinical signs. The owner reported a return to normal gait and exercise at 9 months follow-up. Conclusion: To the authors’ knowledge, this is the first case report to describe the presentation, investigations and management of suprascapular nerve injury in a dog. Traumatic injury of the suprascapular nerve, although rare, should be considered in dogs presented with unilateral thoracic limb lameness. Accurate diagnosis and appropriate management of the condition could lead to favourable outcome.